Pressure controlled variable pump output by-pass system

ABSTRACT

An axial pump having the capability of providing a plurality of independently adjustable fluid flows wherein there is an orifice network for returning adjustable amounts of pumped fluid from each piston to the inlet chamber depending on detected control pressures. A series of poppets are spring biased across orifices and the poppets adjust the open orifice period depending on the detected control pressures. The pump uses segmented bearings for its cam plate in combination with the aforesaid variable flow capacity. The pump further includes the use of a divided barrel wherein one portion houses reciprocating pistons and the other portion consists of a replaceable end-plate having passageways and valving means therein for determining the number of outputs and which of these outputs will be variable or fixed flow.

United States Patent [15] 3,692,052 Cattanach 1 Sept. 19, 1972 [54] PRESSURE CONTROLLED VARIABLE 2,414,629 1/1947 Bloss ..25 l/63.6 PUMP OUTPUT BY-PASS SYSTEM 2,532,607 12/1950 Churchman ..137/1 15 [72] Inventor: Hamish A. G. Cattanach, 140 Fulwe" Teddington Nfiddlese"y Primary ExamlnerWllllam R- Chine England Attorney-Robrllard & Byrne [22] Filed: March 27, 1970 57 ABSTRACT PP N04 29,720 An axial pump having the capability of providing a Related us. Application Data plural ty of independently ad ustable fluid flows wherein there IS an orifice network for returning ad- Division Of 733,050, June 1968, justable amounts of pumped fluid from each piston to ba on the inlet chamber depending on detected control pressures. A series of poppets are spring biased across ori- U-S. Cl. ..l37/561, 137/569, 417/299 flees and the poppets adjust the open orifice period [5 depending on the detected control pressures The [58] Field of Search ..l37/56l, 569, 115; 251/63, pump uses segmented hearings for its cam plate in 251/633 63-5? 417/299 31 l combination with the aforesaid variable flow capacity. The pump further includes the use of a divided barrel [56] References C'ted wherein one portion houses reciprocating pistons and UNITED STATES PATENTS the 0ther portion consists of a replaceable end-plate having passageways and valvmg means therein for 2,665,552 1/ 1954 Deardorff ..417/307 X determining the number of outputs and which f these 3,425,218 2/1969 Attebo ..417/299 outputs will be variable or fixed flow 3,195,556 7/1965. Norstrad et al ..l37/l15 3,343,217 9/1967 Daubenberger ..l37/115 X 7 Claims, 8 Drawing Figures PATENTEDSEP 19 I972 SHEET 1 [IF 4 Rm 5 NT Mr M PATENTEDSEP 1 I912 3.692.052

SHEET 3 [1F 4 INVENTOR HAM/SH GATT'ANACH er MJ ATT NEYS fluid pump wherein variable flow is obtained and adjusted in accordance with control requirements.

An objective of this invention is to provide a fluid pump wherein a by-pass system is provided between the pressurized end of the piston chambers and the intake chamber which by-pass system is closed during certain portions of the power stroke in accordance with control pressures.

Another objective of this invention is to provide a hydraulic pump which has the capability of providing two or more independently controlled variable flows from a unit driven by a common power source.

A further objective of this invention is to provide a multi-output fluid pump having a divided barrel housing having a first portion of standardized elements receiving the reciprocating pistons and a second endplate, manifold portion for determining the number and character of the separate fluid outputs.

Another important objective of this invention is to provide a novel fluid translator wherein the axial forces are absorbed by a plurality of segmented bearings between the rotary cam plate and the pump housing together with means for automatically obtaining a plurality of automatically adjustable fluid outputs.

A still further objective of this invention is to provide a hydraulic pump with a spring-biased poppet across a by-pass passageway between the output end of the piston chambers and the intake chamber with means for determining the length of time the poppet remains open during the power stroke.

Another important objective of this invention is to provide a pump of the type described wherein the results in performance thereof are not materially affected by changes in operating pressures and temperatures.

Another important objective of this invention is to provide a fluid pump of the type described which has a plurality of outputs each of which is independently variably controlled while maintaining a construction of extreme durability, simplicity, and economy of design.

A further objective of this invention is to provide a fluid control device for each piston for determining in response to control pressures the amount of fluid which is by-passed to the intake side of pump during the pumping strokes.

Another objective of the invention is to provide a coverlet assembly for a fluid translator which increases the flexibility of the translator while maintaining a standardization of parts.

A still further objective of this invention is to provide a flow control by-pass valve dependent on a control pressure. More particularly, this objective is acquired through the use of a spring-biased poppet received in a T-network passageway having one end communicating with the flow line a second end communicating with a return line passageway, and the third end thereof communicating with, or sensitive to the control pressure.

These and other objects of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings, wherein:

FIG. 1 is a longitudinal cross-section of the fluid translator of this invention;

FIG. 1a is a diagrammatic enlargement of the by-pass of FIG. 1;

FIG. 2 is a partial cross-section showing the ease with which variable multi-independent fluid flows are obtainable;

FIG. 3 and FIG. 4 are schematics showing typical systems in which the pump of this invention is used;

FIG. 5 is a vertical cross-section through the endplate of a further embodiment of the invention;

FIG. 6 is a diagrammatic vertical section through FIG. 5 showing a manifold system; and

FIG. 7 is a partially diagrammatic view of a coverlet assembled for FIG. 5.

Referring now to the drawings wherein like numerals indicate like parts, the numeral 10 refers to the hydraulic pump of this invention. The pump housing is comprised of three basic units; namely, an inlet housing 12, a piston carrier section 14, and an end plate 16. The three units 12, 14 and 16 are fitted securely together by conventional sealing and bolting means such as seals 15 and a plurality of circumferentially arranged bolts 17. A locating pin 19 is used to facilitate alignment.

A power driven shaft 18 extends into the housing 12. Secured to the shaft is a rotating cam plate 20 having an inclined surface 22. The shaft is rotatably secured within the unit 12 by a bearing assembly generally referred to as 24 and the axial forces thereof are absorbed by a segmented bearing assembly generally referred to by the numeral 26. The bearings in their operation are more fully described in assignees copending application Ser. No. 588,211, filed Dec. 5, 1966, entitled Segmented Oil Film Bearing for Fluid Translator.

The carrier 14 is counterbored at 28. Disposed within the counterbore 28 is an annular stabilizing sleeve 30 having a series of longitudinal passageways 32 therethrough. The inner end of shaft 18 is rotatably secured by a bearing assembly 33 which is located in teriorly of the sleeve 30. Spacedradially outwardly from counterbore 28 are a plurality of circumferentially arranged cylinder bores 36 each of which receives a reciprocating piston 38. The pistons are hollow and are caused to travel through power and discharge strokes as more fully described in my aboveidentified copending application. The pistons 38 have interior check valve apparatus as disclosed in the assignees Stewart US. Pat. No. 25,850, issued Sept. 7, 1965.

As will be understood by those skilled in the art, the pistons receive fluid into their interior through apertures 40 during their intake stroke and discharge fluid into an exhaust manifold 42 through one-way checks 44 disposed between the piston chambers and the discharge chamber.

As seen best in FIG. 1, each of the pistons 38 is partially received at the end of its discharge stroke by circular depressions 46 formed in the inner surface 48 of the end-plate l6 opposite each of the cylindrical bores 36. Pressurized fluid in these depressions is communicated to the exhaust manifold 42 by way of openings 50 which provide a valve seat for one-way checks 44.

The end-plate 16 is counterbored as shown by the lines 52 in FIG. 1. Within this counterbore, a by-pass unit 54 is received. For purposes of discussion, the bypass unit 54 is considered a part of the end-plate 16. The unit 54 is fitted into the depression 52 and it is a separate piece only because it simplifies the boring of certain passageways. The by-pass unit 54 is formed with a plurality of radial passageways 56. The outer enlarged ends 58 of the passageways are in communication with their respective depressions 46. As shown in FIG. 1, two of the passageways 56 are shown interconnected by a passageway 60, respectively, through control orifices 61. The connecting passageway 60, in turn, is connected to a pressure sensor by way of a conduit 62.

The by-pass unit 54 is counterbored at 64 which together with center opening 68 in piston carrier 14, the slots 32 in sleeve 30, and the openings 70, communicates the radial bores 56 to the intake chamber of housing 12.

Intermediate the lengths of the radial passageways 56 are seats 72 which are adapted for closing by the conical surfaces 74 of poppet members 76. The poppet members 76 further include inner pistons 78 slidably received in the inner portions of bores 56. The pistons 78 are connected to the closures 74 by way of stems 80 of reduced diameter. The poppets can be spring biased radially inwardly against the seats 72 by way of springs 82. The springs extend between the closures 74 and retaining spider-type washers 84. The by-pass units are best understood by reference to the diagrammatic of FIG. la.

In operation, the pistons 38 pump pressurized fluid to the discharge port 42 through the depressions 46 and passageways 50 past the checks 44. Return flow from the discharge port 42 is, of course, not permitted by these one-way checks. If closures 74 are fully seated in during their suction stroke because of the difference in pressure between the piston chambers and the intake chamber. This permits an additional avenue by which oil can be sucked into the piston chamber.

In the event there is a pressure rise sensed in control passage 62, this pressure is reflected in the passageway system 60. This retards the closing of poppets 76 on their seats 72 during a portion of the discharge stroke. This permits a certain by-pass flow through orifice 70 into the intake chamber. The amount of time closure 74 is spaced from seat 72 will depend in part on the pressure drop caused by flow across the poppet seat and the level of this control pressure. It will also depend on the rate of spring decay when a spring is utilized.

During the suction strokes of the pistons, fluid not only enters the pumping chambers through spertures 40 but fluid is also drawn from the chamber network associated with chamber 64. In other words, the poppets are open (as shown in the upper by-pass of FIG. 1) during the suction phase of a stroke. The length of time the poppet remains open during the discharge stroke will depend in part on the pressure drop resulting from the rate of oil flow through the poppet seat and this is influenced on the level of control pressure on poppet pistons 78.

The instant invention takes advantage of the multiflow advantages of the invention described in the Blair patent issued on June 21, 1960, as US. Pat. No. 2,941,475. In the Blair patent there is disclosed a means by which the plugs 23 are removed and isolating sleeves are inserted therein as shown in FIG. 2. Thus, if a desired number of isolating sleeves are inserted, any number of plurality of outputs is obtainable by way of exterior manifolds. In order to obtain the multi-flow advantages by using the Blair sleeves, additional threading at 91 is provided.

Referring again to FIG. 1, it is seen that passageway 60 communicates with two of the passageways 59. Thus, a pump having 10 pistons and all the pistons collected in pairs in a like manner provides a total of five controlled outputs. However, those skilled in the art will appreciate that a sensing passageway 60 could be extended to each output and each output provided with an isolating sleeve. Therefore, a ten piston pump can theoretically have ten independently variable outputs or any combination of fixed and variable outputs. For a fixed output, passageway 58 can be plugged which eliminates all by-pass flow.

The schematic of FIG. 4 discloses a second output 94 leading to a second load having an independent sensing line 62' leading to a separate group of piston outputs. It is seen that a plurality of adjustable variable flows is obtained from a single pump by using the teachings of this invention.

As previously mentioned, the decay in springs 82 resulting from a certain detected control pressure will partially determined the time period fluid is by-passed (returned) to the intake chamber during a pumping stroke. This period is quite accurately determined by selecting the strength characteristics in spring 82, the size of the control orifice 61 between passageways 59 and 60, and the control pressure. A pressure reducing valve 92 can be interposed along the length of the sensing conduit as shown in FIGS. 3 and 4 such that field adjustments of control pressure are possible. The utilization of springs 82 have the effect of increasing volumetric efficiency and control.

The elements 14 and 16 can be termed a barrel assembly. The barrel assembly is divided into two com ponents on either side of the plane 96 of FIG. 1. With this arrangement, an economy of manufacture is obtained by standardizing the components to the left of plane 96. The number and character of the flows obtainable from the pump can then be determined by selecting an end-plate 16 of the desired construction. For instance, although components 12 and 14 are standardized, a manufacturer can offer a pump having as many outputs as there are pumping pistons and can provide a variable flow to as many of these flows as desired by the manifolding design and poppet placement of end-plate 16. The embodiment of FIGS. 57 is especially able to accomplish the objective of a large number of independently variable outputs. In FIG. 5, the elements to the left of plane 96 are the same as in FIG. 1 except the outer strokes of pistons 38 are designed to terminate just prior to reaching the plane 96.

The pistons 38 each exhaust into bores 100 formed in the face 102 of an end-plate 104. The bores 100 communicate the piston outputs to an output passageway such as that shown by the numeral 110. Press-fitted into the bores are sleeves 106 having perforations 108 intermediate their lengths leading to annular groove 109. Valve seats 112 are found at the ends of sleeves 106 which receive one-way check balls 114. The halls are biased against the valve seats by springs 116 which circumscribe locating pins 118.

In FIG. 5, the by-pass units are received in axial bores 120 rather than in radial bores as disclosed in FIGS. 1 and 1a. The bores 120 are communicated to the outputs of the pistons 38 through passageways 122. The by-pass units each include a sleeve 124 having perforations 125 leading to a peripheral groove 126 intermediate the sleeve length. A valve seat 127 is found at the inner of the sleeve for reception of a ball valve 128. The ball valve 128 is spring-biased against the valve seat by a spring 130 that surrounds a positioning pin 132. Reciprocally received within the interior 134 of the sleeve 124 is a poppet piston 136. The piston has a stem 137 for unseating ball 128 and at its other end a surface 139 facing the control pressure. An orifice ring 140 is disposed between the surface 139 and the control pressure.

In order to obtain a desired number of independent outputs, the end-plate 104 is provided with a coverlet 158. If the entire pump output is varied by a single control pressure, the chambers 134 are communicated with the detected pressure passageway 62a by an annular groove 140. The pumping piston outputs are collected by output passageway 110 and delivered to the load via output 142.

When more than one output is desired, and these outputs are to be adjusted by different control pressures, a multiple coverlet assembly is used. For instance, if two independently variable outputs are desired, an intermediate coverlet (FIG: 7) is provided. The intermediate cover on its side remote from the end-plate is annularly grooved at 152 and 154. These grooves are each respectively in communication with control pressure ports 156 and 158 formed in an outer coverlet 160. The particular set of piston outputs grouped for control by the control pressure sensed in port 156 have their by-pass sensing units communicated with groove 152 by bores 172 formed in coverlet 150. The other group of outputs have their by-pass sensing units communicated with the groove 154 by slant bores 176. If three variable outputs are required, a third independent groove is formed in the coverlet 150.

Presuming for a ten piston pump it is desired to have three outputs; namely, a first variable output of three pistons, a second variable output of two pistons and a fixed output of five pistons. In order to accomplish this, the end-plate is formed with a first manifold collecting three pistons outputs each having a by-pass unit, a second manifold collecting two other piston outputs each having a by-pass unit, and a third manifold collecting the five remaining outputs.

As seen in the diagrammatic of FIG. 6, piston outputs A, B, C, D and E are joined by a pair of manifold passageways and 172. The outer end of passageway 170 is plugged at 174 while the outer end of 172 leads to an outlet port 144. The by-pass passageways associated with outputs A-E, inclusive, are plugged since these five outputs are for fixed displacement. Piston outputs F and G are joined by a separate manifold passageway 176 which leads to outnicated by a manifold passageway 180 leading to an outlet 182. As seen in FIG. 7, the by-pass units associated with grouping F and G are conveniently communicated with the control pressure 156 and the grouping I-I-I-J are conveniently communicated with the control pressure 158.

In actual practice, improved efficiency is gained by not connecting adjacent outputs to the same outlet. The actual borings in the embodiment of FIGS. 5-7 can be located at various places. Here, adjacent manifold bores are grouped for purposes of clarity, but those skilled in the art will recognize that the location of actual borings can depend on several manufacturing considerations such as spacing and the strength of material. Normally, it is best to have several pistons of a particular group traversing their exhaust strokes while others of the same group are traversing their power strokes. It should be noted, however, that the provision of a coverlet system for communicating the by-pass sensors to their control pressures is equally efficient as a fluid collection device regardless of which piston outputs are grouped together. In the coverlet system, a concentric collection groove is formed for each variable output group and bores are drilled to communicate these grooves to their respective by-pass sensors.

In a general manner, while there has been disclosed effective and efficient embodiments of the invention, it should be well understood that the invention is not limited to such embodiments, as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

lclaim:

1. A fluid control device for use in controlling the fluid flow in a fluid flow line comprising, a first passageway forming a part of the fluid flow line and having an inlet end and an outlet end, a second passageway having a first end in'communication with and intermediate the ends of said first passageway and a second end, a third passageway having one end communicating with said second passageway intermediate the length of said second passageway and a second end leading to a control pressure, controller means disposed in said third passageway between said control pressure and said second passageway and moveable responsive to said control pressure, valve means in said second passageway operably connected to said controller means for movement between open and closed positions whereby said flow in said first passageway is selectively communicated to said second end of said second passageway, said control pressure acting in a direction to maintain said valve in an open position until such time as the force developed by said fluid flow overcomes said control pressureto close said valve, and a restricted orifice in said third passageway between said controller means and said control pressure.

2. The fluid control device of claim 1 including a second valve means located at said outlet end, and biasing means closing said second valve means until such time as said first valve means is closed by the force of 3. The fluid control device of claim 1 wherein said valve means includes a valve seat between said first and second passageways, and a closure connected to said controller means, and wherein said controller means is a piston slidably received in said third passageway between said second passageway and said control pressure.

4. The fluid control device of claim 3 wherein said force is developed by restriction means in said second passageway defined by said valve seat and said closure.

5. The fluid control device of claim 3 wherein a stem of reduced cross-section relative to said piston con- 

1. A fluId control device for use in controlling the fluid flow in a fluid flow line comprising, a first passageway forming a part of the fluid flow line and having an inlet end and an outlet end, a second passageway having a first end in communication with and intermediate the ends of said first passageway and a second end, a third passageway having one end communicating with said second passageway intermediate the length of said second passageway and a second end leading to a control pressure, controller means disposed in said third passageway between said control pressure and said second passageway and moveable responsive to said control pressure, valve means in said second passageway operably connected to said controller means for movement between open and closed positions whereby said flow in said first passageway is selectively communicated to said second end of said second passageway, said control pressure acting in a direction to maintain said valve in an open position until such time as the force developed by said fluid flow overcomes said control pressure to close said valve, and a restricted orifice in said third passageway between said controller means and said control pressure.
 2. The fluid control device of claim 1 including a second valve means located at said outlet end, and biasing means closing said second valve means until such time as said first valve means is closed by the force of said fluid flow.
 3. The fluid control device of claim 1 wherein said valve means includes a valve seat between said first and second passageways, and a closure connected to said controller means, and wherein said controller means is a piston slidably received in said third passageway between said second passageway and said control pressure.
 4. The fluid control device of claim 3 wherein said force is developed by restriction means in said second passageway defined by said valve seat and said closure.
 5. The fluid control device of claim 3 wherein a stem of reduced cross-section relative to said piston connects said piston and said closure.
 6. The fluid control device of claim 3 wherein a spring biases said closure and piston toward the closed position.
 7. The fluid control device of claim 1 and including a fluid delivery means for delivering the fluid flow to said first passageway at a flow rate generally following regular cyclic patterns, and wherein said valve means is opened and closed during selected phases of said cyclic patterns in response to said flow rate. 